Molecular para-hydrogen cluster with N=5 molecules. Each hydrogen molecule is represented by a rigid rotor or dumbbell with bond length r=0.767A (shown to scale). The five green dumbbells represent one possible realization or snapshot (similarly for the blue and red dumbbells). The gray sphere illustrates the ``size'' of the N=5 cluster (R=4.21A), which is defined here so that 95% of the hydrogen molecules are contained in the corresponding volume. Clearly, molecular para-hydrogen clusters are highly diffuse quantum objects for which a classical description is insufficient.